Offshore oil and natural gas exploration and production utilize above-sea platforms to support drilling and/or processing equipment for extracting resources from subsea wells. The above-sea platforms mount to a system of fluid transfer and mooring lines extending from the platforms to the sea floor. The platforms may include drilling systems, transport systems, support equipment, such as electrical power generation, and crew accommodations. In addition to above-sea platforms, many offshore operations include subsea platforms to support various systems at or near the sea floor.
Subsea platforms may include sub-systems, which are transported to a particular site, submerged, integrated to form one or more subsea systems, and tested. Current technology limits transport and positioning of each sub-system to be less than 500 metric tons (MT). Therefore, installation of the subsea platform may be a lengthy process depending upon size, weight, and number of sub-systems. More specifically, a subsea system may require multiple support ships to transport and position each sub-system as well as a lengthy construction and testing phase prior to being ready for operation.
One issue with deploying the subsea platform relates to a lack of desirable options for providing buoyancy. High pressure in deepwater environments, with depths exceeding 3000 meters, and economical constraints contribute to problems associated with designing the buoyancy. High pressure and economic constraints also impact other subsea tank based applications, which may employ corresponding designs as used for the buoyancy tank.
Therefore, a need exists for subsea vessels to provide cost effective options for deepwater applications, including buoyancy during deployment of subsea platforms.